In a fire, the victims are not only subjected to the flames but also to a multitude of noxious gases. Eighty percent of the deaths due to such fires are caused by noxious gas inhalation. In order to survive the toxic environment associated with fires, victims need to reach breathable air or a smoke mask in one to four minutes.
A typical smoke mask arrangement is shown in U.S. Pat. No. 2,810,386 entitled "Oxygen Masks Embodying Means for Ventilating Goggles" by W. B. Reed. Commonly used smoke mask filter materials are disclosed in U.S Pat. No. 4,046,939 entitled, "Gas Resistant Foam Materials" by Hart. Polyurethane foam impregnated with activated carbon particles is used. The foam is highly resistive to the passage of noxious gases and the carbon particles adsorb various noxious gases.
The need to adsorb specific noxious gases was recognized in U.S. Pat. No. 4,297,117 entitled, "Respiratory Device for Catastrophic Fires and/or Smog Weather Conditions" by Holter et al. The patent discloses the use of adsorptive materials such as: cuprous oxide, manganese dioxide, calcium aluminum-silicate, soda lime and activated carbon.
Because fires are often associated with a low visibility environment due to smoke and loss of lighting, smoke masks made entirely of transparent plastic have been made, for example as illustrated in U.S. Pat. No. 2,850,011 entitled, "Respiratory Helmet" by Schaefer. The transparent mask affords maximum vision therethrough and is readily positionable. The mask uses an oxygen canister to supply breathable air.
Therefore, an object of the present invention is to provide a compact, lightweight breathing hood which is readily positionable.
A further object of the present invention is to provide a breathing hood which provides good visibility and maximum noxious gas protection.
A further object of the invention is to also provide a breathing hood which provides head, neck and face thermal protection from a fire.